1. Field of the Invention
The present invention relates to a fluid nozzle for the atomization of liquids and, more particularly, relates to a three-fluid nozzle for effectuating a unique method of atomizing high viscosity liquids and difficult-to-spherize liquids which are to be spray-dried. Furthermore, the invention also relates to a novel method of atomizing high viscosity liquids and liquids which are difficult to spherize in an essentially two-step atomization sequence through the utilization of the inventive three-fluid atomizing nozzle.
Conventional methods of spray-drying materials which contain solids dispersed in a solution or suspension, such as, for instance, gelatin, coffee extract, lemon juice and the like, generally involve the step of ejecting the solution or suspension which is to be spray-dried downwardly from a nozzle into a heated environment, such as into a drying tower. Thus, the spraying or ejection of the solution or suspension from the nozzle produces a formation of droplets or discrete liquid particles, wherein the droplets then fall downwardly through the drying tower, and in which the resultant rapid evaporation of water or other solvents from the material being spray-dried causes the formation of a substantially dry, particulate free-flowing material. For this purpose, numerous types of atomizing nozzle designs and spray-drying methods have been developed in the technology relating to the spray-drying of these various viscous solutions or suspensions, hereinafter referred to as liquids. However, considerable difficulties have been encountered in the formation of the droplets or small spheroids from the liquids being discharged from the atomizing nozzle. Quite frequently, in lieu of the formation of droplets or discrete particles in the heated atmosphere of the spray-drying tower, there are frequently encountered undesirable formations of filaments and other irregularly dried product shapes which render current spray-drying methods for liquids or slurries containing high percentages of solids concentrations to be uneconomical and, depending upon conditions, not even feasible. In particular, disadvantages which are encountered in prior art methods of spray-drying liquids of the type under consideration relate to the use of two-fluid nozzles; in effect, nozzles which eject the liquid which is to be spray-dried and an atomizing fluid, such as, for example, steam or air, wherein these fluids are usually atomized within the nozzles, and in which the liquids are restricted to only relatively low concentrations of solids dispersed therein to allow for functioning of the nozzles.